1. Field of the Invention
The present invention relates to a flat panel display device and, more particularly, to an organic electroluminescent (OEL) display device suitable for displaying various kinds of information and images.
2. Description of Related Art
Organic electroluminescent display devices become focus among various flat panel display devices in recent years because of their advantage of spontaneous emission. In other words, the pixels on the organic electroluminescent display device are capable to display colored images without external backlight modules. Therefore, an organic electroluminescent display device can be a suitable flat panel display device for future applications owing to the advantages of lightweight, compact-size, and thin-thickness.
Generally speaking, the panel of the organic electroluminescent display device is divided into two areasxe2x80x94i.e. an active area and a lead-out area for conducting lines. In most cases, the electrical current is transmitted through the conducting lines to the electrode lines in the active areas. In most current OLED panel, each conducting line is composed of a transparent electrical conducting layer and fine auxiliary metal (e.g., chromium) lines mounted in the layer of transparent electrical conducting layer for increasing the current density therein and simplifying the manufacturing process of the display panel. However, the stacked structure of the conducting lines are easily deteriorated or peeled off due to the damages caused by environmental moisture, oxygen or the frequent driving of electrical currents. As a result, some problems, such as burnout or short circuit occurs frequently in the conducting lines which connect the electrodes in the active area of the conventional electroluminescent display device and the external parts (e.g. ICs). The problems caused from the damages made by moistures, and other electrical factors often lead to unusual deterioration of display qualities. For example, an abnormal bright line (or bands) or an abnormal dark line (or bands) occasionally shows up on the OLED display panel. Moreover, the lifetime of the electroluminescent display device is shortened. Owing to the deterioration of the display quality, the yield for manufacturing OLED is also decreased.
Therefore, it is desirable to provide an organic electroluminescent display device and method for packaging the same to mitigate the aforementioned problems.
The present invention is to provide an organic electroluminescent display device to reduce or prevent the damage to the conducting lines caused by the environmental moisture and oxygen, to avoid the burnout or short circuit happening to the conducting lines, to improve the display quality, to extend the lifetime of the OLED, to improve the manufacturing yield of display panel, and to reduce the cost of the wasted panels.
The present invention is also to provide a method for packaging an organic electroluminescent display device to reduce or prevent the damage to the conducting lines caused by the environmental moisture and oxygen, to avoid the burnout or short circuit happening to the conducting lines, to improve the display quality, to extend the lifetime of the OLED, to improve the manufacturing yield of display panel, and to reduce the cost of the wasted panels.
In accordance with the present invention, the organic electroluminescent display device of the present invention comprises: a substrate having a first conducting area, a second conducting area, and an active area; wherein said active area locates adjacent to said first conducting area and said second conducting area; a plurality of connecting wires, which do not connect with each other and are located outside said active area on said substrate; a plurality of stripes of first electrodes located in said active area, wherein said first electrodes connect to said connecting wires; a plurality of first conducting lines, which do not connect with each other and are located in said first conducting area on said substrate; a plurality of second conducting lines, which do not connect with each other and are located in said second conducting area on said substrate; a plurality of second electrodes located in said active area, wherein each of said second electrodes connects a first conducting line or a second conducting line; at least one organic electroluminescent medium located in said active area, wherein said organic electroluminescent medium is sandwiched between said first electrode and said second electrode; an upper cover mounted over or on said active area of said substrate for covering said active area; a sealing layer sandwiched between said upper cover and said substrate for sealing, surrounding said active area, and isolating said active area from air or moisture; and an insulating layer filled over said first conducting lines, said second conducting lines, and said connecting wires for isolating said first conducting lines, said second conducting lines, and said connecting wires from air or water; wherein part of each first electrodes, each first conducting lines, each second conducting lines, and each connecting wires has at least one auxiliary metal layer and one transparent electrical conducting layer, and said transparent electrical conducting layer is sandwiched between said auxiliary metal layer and said substrate.
The panel for an organic electroluminescent display device of the present invention includes: a substrate having a first conducting area, a second conducting area, and an active area; wherein said active area locates adjacent to said first conducting area and said second conducting area; a plurality of connecting wires located outside said active area on said substrate, wherein said connecting wires do not connect with each other; a plurality of stripes of first electrodes located in said active area, wherein said first electrodes connect to said connecting wires; a plurality of first conducting lines located in said first conducting area on said substrate and do not connect with each other; and a plurality of second conducting lines located in said second conducting area on said substrate and do not connect with each other; wherein each first conducting line, each second conducting line, and each connecting wire in said active area has at least one transparent electrical conducting layer and optionally an auxiliary metal layer, said transparent electrical conducting layer is sandwiched between said auxiliary metal layer and said substrate; and no auxiliary metal layer exists in each first conducting lines, each second conducting lines, and each connecting wires outside said active area.
The organic electroluminescent display device of the present invention includes: a substrate having a first conducting area, a second conducting area, and an active area; wherein said active area locates adjacent to said first conducting area and said second conducting area; a plurality of connecting wires located outside said active area on said substrate, wherein said connecting wires do not connect with each other; a plurality of stripes of first electrodes located in said active area, wherein said first electrodes connect to said connecting wires; a plurality of first conducting lines located in said first conducting area on said substrate and do not connect with each other; a plurality of second conducting lines located in said second conducting area on said substrate and do not connect with each other; an upper cover mounted over or on said active area of said substrate for covering said active area; and a sealing layer sandwiched between said upper cover and said substrate for sealing, surrounding said active area, and isolating said active area from air or moisture; wherein each first conducting line, each second conducting line, and each connecting wire in said active area has at least one transparent electrical conducting layer and optionally an auxiliary metal layer, said transparent electrical conducting layer is sandwiched between said auxiliary metal layer and said substrate; and no auxiliary metal layer exists in each first conducting lines, each second conducting lines, and each connecting wires outside said active area.
The method for manufacturing an organic electroluminescent display device of the present invention comprises the following steps: (A) forming an active area, a plurality of stripes of first electrodes, a plurality of connecting wires, a plurality of first conducting lines, and a plurality of second conducting lines on a substrate; wherein said first electrodes are located in said active area of said substrate, and each of said first electrodes connects to one of said connecting wires; said first conducting lines are located outside said active area on said substrate and do not cross with each other; said second conducting lines are located outside of said active area on said substrate and do not cross with each other; and part of each first electrode, each first conducting line, each second conducting line, and each connecting wire has at least one auxiliary metal layer and one transparent electrical conducting layer, and said transparent electrical conducting layer is sandwiched between said auxiliary metal layer and said substrate; (B) forming at least one organic electroluminescent medium and a plurality of stripes of second electrodes in said active area, and forming an insulating layer on parts of said first conducting lines, said second conducting lines, and said connecting wires outside of said active area for insulating from air or moisture; wherein at least said a plurality of second electrodes and said organic electroluminescent medium are located in said active area of said substrate, said organic electroluminescent medium is sandwiched between said second electrodes and said first electrodes, each of said first electrodes do not directly connect to said second electrodes, and each of said second electrodes connects to one of said first conducting lines or one of said second conducting lines; and (C) covering an upper cover on said active area and forming a sealing layer between said upper cover and said substrate; wherein said first conducting lines, said second conducting lines, and said connecting wires located outside of said sealing layer are covered by said insulating layer.
The method for manufacturing an organic electroluminescent display device of the present invention includes the following steps: (A) forming a plurality of stripes of first electrodes, a plurality of connecting wires, a plurality of first conducting lines, and a plurality of second conducting lines on a substrate having an active area, a first conducting area, and a second conducting area; wherein said active area locates adjacent to said first conducting area and said second conducting area, said connecting wires located outside said active area on said substrate; said first electrodes are located in said active area of said substrate, each of said first electrodes connects to one of said connecting wires; said first conducting lines are located outside said active area on said substrate and do not cross with each other; said second conducting lines are located outside said active area on said substrate and do not cross with each other; each first conducting line, each second conducting line, and each connecting wire in said active area has at least one transparent electrical conducting layer and optionally an auxiliary metal layer, said transparent electrical conducting layer is sandwiched between said auxiliary metal layer and said substrate; and no auxiliary metal layer exists in each first conducting lines, each second conducting lines, and each connecting wires outside said active area; (B) forming at least one organic electroluminescent medium and a plurality of stripes of second electrodes in said active area; wherein at least said second electrodes and said organic electroluminescent medium are located in said active area of said substrate, said organic electroluminescent medium is sandwiched between said second electrodes and said first electrodes, each of said first electrodes do not directly connect to said second electrodes, and each of said second electrodes connects to one of said first conducting lines or one of said second conducting lines; and (C) covering and binding an upper cover on said active area and forming a sealing layer between said upper cover and said substrate; wherein said first conducting lines, said second conducting lines, and said connecting wires located outside said sealing layer do not have said auxiliary metal layer.
The display driving mechanism of the active area of the organic electroluminescent display device of the present invention can be any conventional display driving mechanism. Preferably, the display driving mechanism of the active area is passive or active. The relative position of the first conducting area and the second conducting area to the active area of the organic electroluminescent display device of the present invention is not restricted. Preferably, the distribution of the conductive lines is X-Y matrix distribution surrounding the active area, bilaterally top-bottom distribution surrounding the active area, or symmetrically left-right distribution surrounding the active area. The active area is located adjacent to the first conducting area and the second conducting area. Preferably, the active area is located between the first conducting area and the second conducting area. The numbers of the first conducting lines and the second conducting lines of the present invention are not limited. Preferably, the number of the first conducting lines and that of the second conducting lines are the same. The first electrodes, the first conducting lines, the second conducting lines, and the connecting wires of the organic electroluminescent display device of the present invention have transparent electrical conducting layers for conducting the electrical signals. Optionally, they also have auxiliary metal layers for increasing the electrical conductivity. The materials of the auxiliary electrodes of the first electrodes, the first conducting lines, and the second conducting lines can be any conventional conductive materials. Preferably, the auxiliary electrodes of the first electrodes, the first conducting lines, and the second conducting lines are made of aluminum (Al), chromium (Cr), or silver (Ag) alloys. In addition, the active area of the organic electroluminescent display device of the present invention can optionally include a plurality of isolating walls located between the second electrodes in the active area or selectively on the first electrodes. A plurality of pixel-defining layers is preferably formed in the active area for insulating and defining the areas of the organic electroluminescent media. The materials of the pixel-defining layer can be any conventional material for shading light or insulating electrical currents. Preferably, the pixel-defining layer is made of polyimide. The materials of the first electrodes can be any conductive materials. Preferably, the first electrodes are made of transparent conductive materials. More preferably, the transparent materials are selected from InSnO3, SnO2, ZnO-doped In2O3, CdSnO, or antimony. The materials of second electrodes can be any electrically conductive material. Preferably, the second electrodes are made of aluminum, diamond, diamond like carbon (DLC), calcium, aluminum-silver alloy, or magnesium-silver alloy. The arrangement of the first electrodes is not restricted, and is preferred to be parallel to each other. The arrangement of the second electrodes is not restricted, and is preferred to be parallel to each other. The method for manufacturing an organic electroluminescent display device of the present invention can be achieved by optionally form a pixel-defining layer before the formation of the organic electroluminescent medium and the second electrodes in the active area are completed. In other words, a plurality of pixel-defining layers are formed first on the substrate for insulating and defining the areas of the organic electroluminescent media, wherein each of the pixel-defining layers is located between the adjacent organic electroluminescent media on the substrate or on the first electrodes. The method for manufacturing an organic electroluminescent display device of the present invention also includes the step of optionally forming a plurality of isolating walls before forming the organic electroluminescent medium and the second electrodes in the active area. The isolating walls are located between the adjacent second electrodes on the substrate or the first electrodes. The organic electroluminescent medium of the present invention can be made of the small organic molecules or polymers. Furthermore, the organic electroluminescent medium can optionally include an electron injecting layer, an electron transporting layer, a hole transporting layer, and a hole injecting layer. The active area can be further sealed with an upper cover for preventing moisture, or any sensitive chemical pollutants (e.g. oxygen, oxide, or sulfide in the air). Moreover, the external integrated circuit chips can be bonded on the substrate through COG (chip on glass) bonding. The materials of the insulating layers of the present invention could be made of any known organic or inorganic material that is capable of insulating moisture or oxygen. Preferably, the insulating layer is made of SiO2, TiO2, silicon nitride, epoxy resin, unsaturated polyester resin, Teflon(trademark) resin, phenolic resin, or polyimide. The method for forming the insulating layer can be any conventional method. Preferably, the insulating layer is formed through evaporation, sputtering, immersion plating, or spraying.
In one aspect, the organic electroluminescent display device and method for packaging the same of the present invention prevents the first conducting lines, the second conducting lines, and the auxiliary metal layers of the connecting wires outside the sealing layer from corroding by the moisture or oxygen through covering an insulating layer on the first conducting lines, the second conducting lines, and the auxiliary metal layers of the connecting wires so that the display quality can be improved and the lifetime of the OLED display device can be extended. The method for covering the insulating layer on the first conducting lines, the second conducting lines, and the auxiliary metal layers of the connecting wires can be any conventional method. Preferably, the insulating layer is covered on the first conducting lines, the second conducting lines, and the auxiliary metal layers of the connecting wires by coating, evaporation, or sputtering.
In another aspect, the organic electroluminescent display device and method for packaging the same of the present invention prevents the first conducting lines, the second conducting lines, and the connecting wires from corroding by the moisture or oxygen through peeling off the auxiliary metal layers of the first conducting lines, the second conducting lines, and the connecting wires outside the sealing layer. As a result, only the transparent electrical conducting layers of the first conducting lines, the second conducting lines, and the connecting wires outside the sealing layer are left, the display quality can therefore be improved, and the lifetime of the OLED display device can be extended. The organic electroluminescent display device of the present invention may peel off the auxiliary metal layers of the predetermined parts of the first conducting lines, the second conducting lines, and the connecting wires by etching. Hence, the first conducting lines, the second conducting lines, and the connecting wires are prevented from corroding by the moisture or oxygen successfully, and then the display quality of the OLED display device can be improved and the lifetime of the OLED display device can be extended.
The aforesaid organic electroluminescent display device can be applied to any purpose or apparatus for displaying images, graphics, characters and texts; and preferably, to televisions, computers, information display device of printers, monitors, information display devices of vehicles, the displays of signal machines, information display devices of communication apparatus (such as cell phones, telephones), information display devices of telephones, interactive electronic books, micro-displays, displays of fishing devices, personal digital assistants (PDAs), virtual reality game means, information display devices of simulative flying training, displays of airplane equipment, and displays of visors for video games.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.